SOUTHWEST HARBOR, Maine — Leah Frost never stopped running, but she had stopped competing in the sport for a decade until convinced by a friend earlier this year to try a 10-kilometer road race in Mexico, where she lived at the time.

Suffice it to say she’s regained the racing bug.

Competing in just her second marathon — and running both within a span of two weeks — Frost not only won the women’s division of the Mount Desert Island Marathon on Sunday but became the first woman to complete the scenic 26.2-mile route in less than three hours.

The native of Round Pond who now resides in Glover, Vt., finished in 2 hours, 59 minutes and 45 seconds, well ahead of the previous course record of 3:01:22 run by Leah Jabbour of Halifax, Nova Scotia, in 2011.

“I turned 30 in June,” said Frost, who ran competitively in high school and early in her college career, “and I decided a good goal as a 30-year-old would be to break 3 hours, which I just did for the first time.”

Louie Luchini of Ellsworth, who spent nearly three months away from training this summer to allow an ailing shin to heal, won the overall title for second straight year and third time overall.

The former 11-time All-American at Stanford University, who now serves in the Maine Legislature, did not match last year’s course record of 2:30:41 but settled for a seven-minute victory with his clocking of 2:32:55.

“I just wanted to come out and negative-split the course, start out conservatively and run the second half faster, and that’s what happened,” said the 32-year-old Luchini, who ran the first half of the marathon in 1:17:28 before coming home in 1:15:27.

“I wanted to come back strong the second half and see how I felt. My breathing felt good. My legs didn’t really have the strength but I felt good about today.”

Approximately 1,400 runners turned out for the marathon and a brand new half-marathon added to the day’s activities this year by race director Gary Allen.

Craig Robinson of Scarborough won the 13.1-miler that covered that last half of the marathon course in 1:16:59, while Grace Nash of Newburgh was the women’s champion in 1:40:28.

Frost made her marathon debut Oct. 6 by winning the women’s division of the Maine Marathon in Portland and just missing her three-hour goal with a time of 3:00:47.

“I felt like I raced really poorly two weeks ago,” she said. “I ended up doing pretty well but I ran the first half of the race 12 minutes faster than the second half so I felt really crummy about it. My goal today was to pace myself better and I did that.”

Frost completed the first half of her MDI run in 1:27:39, then ran the final half in 1:32:06 while tracking down Lindsay Willard of Somerville, Mass., to take the lead at Mile 23.

Willard finished second and also topped the previous women’s course record with her time of 3:01:21, while Maddy Hribar of Newburyport, Mass. (3:11:12), Anna Ackerman of Portland (3:17:28) and Talva Parker of Lees Summit, Mo., (3:24:55) completed the top five.

Luchini hadn’t planned to run the race as he continued to round back into form after sitting out most of the summer due to a shin injury he suffered while competing at the Cabot Trail Relays in Nova Scotia over Memorial Day weekend.

“My preparation wasn’t all that I wanted it to be but it had really been coming around lately,” he said. “I wasn’t going to do this but I ran into Gary at a restaurant last weekend and he talked me into it.”

Erik McCarthy of Old Town placed second overall in 2:39:51, followed by Tristan Williams of Jackson, N.H., (2:41:40), six-time race winner David Herr of Canaan, Vt. (2:43:09) and fifth-place Evan Graves of Caribou (2:46:51).

Robinson, a recent graduate of Bentley University in Waltham, Mass., was victorious in his first half-marathon, pulling away from Portland’s Elliot Conrad over the final two miles.

“I’d never done a race longer than 10K before so I didn’t really know what to expect,” said Robinson. “Elliot and I went out the first eight miles pretty much shoulder to shoulder running anywhere between a 5:35 and 6-minute pace per mile. Right at the top of the hill at 11 miles I felt good so I surged on the downhill and kind of pulled away.”

Nash, racing the 13.1-mile distance for just the second time, held off second-place Sara Bradley of Waterford by 11 seconds.

“It was a good day. I started off faster than I expected but I was able to maintain the pace,” said Nash. “The last few miles were a bit tougher because they seemed all uphill, but I did it.”